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8331A: Autocal, manual adjustments and speaker placement

hupsi, modified 5 Months ago.

8331A: Autocal, manual adjustments and speaker placement

Youngling Posts: 6 Join Date: 3/30/20 Recent Posts

Dear Genelec community,

recently I purchased a pair of 8331A. The listening area is quite small (distance between speakers and from each speaker to listening position 1m), unfortunately. Although GLM manages to improve the sound a lot, there are still some songs where sounds ranging from I think 100-150 Hz are quite exaggerrated. So I moved the speakers away from the back wall (distance is about 25 cm now) and installed some absorbers which has improved imaging and reduced bass extension. (I will also install another absorber behind the right speaker.) Furthermore I tried my best and adjusted Autocal's filters manually.

My questions are:

1. As you can see in the attached pictures (..._adjusted) I used most of the available filter slots. I tried editing mostly the existing filters but failed. :-( Does this possibly go along with any disadvantages? Would it be better to tweak only the existing filters?

2. Is there a common rule of thumb which listening distance works best with the 8331As?

3. I tried reducing the distances (speaker to speaker, speaker to listening position) and was not satisfied. While at 1m soundstage is broad reducing it to 80 cm resulted in the sound being too direct ("headphone effect") with zero depth of the soundstage. Could altering the angle between the speaker widen the soundstage at short listening distances?

Best regards, Daniel

lukester, modified 5 Months ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Jedi Knight Posts: 204 Join Date: 4/22/10 Recent Posts

ad1. There is no rules to this. If it's for pleasure and not work, I sometimes relax the GLM filtering for a bit fatter sound.
​​​​​​​If you add new filters or alter existing ones doesn't matter. using less filters to get the same resulting curve might sound better by an esoteric degree.

ad2. your distances sound a bit low, my 8351 are 1,8m apart, my distance from speakers is 1,3m.

ad3. Angle won't do much, drivers aimed at your ears is the game.

 

I think you should try your absorber symmetrically behind speakers. reflection from wall behind PC screen might be a problem.
​​​​​​​You're firing along the short axis of a very small room, which is very problematic.

I'd try and rearrange things so you look out the window.
​​​​​​​Poor desk might need unplesant interaction with a padsaw.

hupsi, modified 5 Months ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Youngling Posts: 6 Join Date: 3/30/20 Recent Posts

Thanks for your quick reply. I will try some repositioning of the speakers and relocate the absobers to make them symmetrical behind the monitor.

I already assumed that placing the desk along the short axis would be better regarding acoustics... However, then I would not be able to open the windows anymore. Maybe a new apartment would be the solution.

My desk disagreed with your suggestion to murder it. ;-) As I am also using it when working from home I need the space on it.

lukester, modified 5 Months ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Jedi Knight Posts: 204 Join Date: 4/22/10 Recent Posts

well,

I'm afraid you'll have to get used to opening the window by climbing on the desk from now on ;)

hupsi, modified 1 Month ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Youngling Posts: 6 Join Date: 3/30/20 Recent Posts
lukester:

well,

I'm afraid you'll have to get used to opening the window by climbing on the desk from now on ;)

 

So I added symmetrical absorbers behind the 8331a speakers and also a subwoofer (7350a). After GLMs "magic" frequency response seems to be about right except for the dip between 85 and 95 hz. I'm quite happy with the result so far. Music can be heard AND felt, the transition of speakers and subwoofer is seemless. I tried different positions (also under the table centered and slightly offset ...) and this seems to be the best by far.

 

 

janne-koo, modified 1 Month ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Padawan Posts: 36 Join Date: 10/26/15 Recent Posts

Perhaps it's just that our heads' width needs to be accounted for, but I find wider speaker placement better at very near field listening, too.

​​​​​​​The most likely source for a 85-95Hz dip would be cancellation, probably from a hard rear wall, might be near impossible to get rid of it. Still, very much worth it to play around with bass management in GLM, with individual crossover frequencies... I let my desktop 8330's run to 55Hz and start the sub at 70 - it just happens to work well here; My most horrible room dip is about 10 Hz lower.

hupsi, modified 1 Month ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Youngling Posts: 6 Join Date: 3/30/20 Recent Posts
janne-koo:

Perhaps it's just that our heads' width needs to be accounted for, but I find wider speaker placement better at very near field listening, too.

That's similar to what I experience ... I will probably widen the speaker arrangement again as it also slightly increases listening distance.

 

"The most likely source for a 85-95Hz dip would be cancellation, probably from a hard rear wall, might be near impossible to get rid of it."

The left speaker which is placed close to the subwoofer has similar dip so your explanation seems right. Not a big deal after all.

 

"I let my desktop 8330's run to 55Hz and start the sub at 70 - it just happens to work well here; My most horrible room dip is about 10 Hz lower."

Thanks for your input. Next weekend I will try some more settings. Maybe 70 Hz is also an option for crossover, but below 70 Hz both main speakers have a dip so lowering crossover frequency even more most likely won't be an option.

By the way: how do you mean "I let my desktop 8330's run to 55Hz and start the sub at 70"? My understanding is that if you set crossover to a certain frequency the main speakers won't run below that.

 

 

 

 

janne-koo, modified 1 Month ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Padawan Posts: 36 Join Date: 10/26/15 Recent Posts

The sub doesn't filter the mains, no matter how you wire it. If you set bass management to individual mode instead of global (the default), you can select different crossover (high pass and low pass) frequencies for the monitors and sub.

​​​​​​​A global 85 Hz crossover was terrible here, I could pinpoint the sub, so I started lowering the crossover frequency and then experimenting with some overlap... Can't say whether this would do any good or just mess up everything for you, just wanted to point out the option - certainly worth a few tries, GLM is so easy to fool around with.

hupsi, modified 29 Days ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Youngling Posts: 6 Join Date: 3/30/20 Recent Posts

Yesterday I created different groups in GLM with crossover settings ranging from 50 Hz to 80 Hz, thankfully the subwoofer cannot be localized in any of them. The only difference between all the settings is that lower crossover results in "thinner" overall bass response. But I guess it's always good to at least know the different options and try them out. So thanks for your explanation, I will definetely try out the individual mode.

costakis, modified 22 Days ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Padawan Posts: 38 Join Date: 2/13/19 Recent Posts

Dear Hupsi, I would like to propose to use REW. There is a room simulator in it with which you can see the response that you can expect with your room dimensions and relative speaker placement. GLM, as any DSP, cannot work miracles in your room. Your speakers are also fantastic in design, they lower the problems of acoustics in rooms but cannot solve all issues. In the end of the day, you hear the room acoustics.  

In my opinion, see the simulator results, try alternative placement of the speakers and if you can buy a subwoofer to ease the placement of the monitors. 

hupsi, modified 17 Days ago.

RE: 8331A: Autocal, manual adjustments and speaker placement

Youngling Posts: 6 Join Date: 3/30/20 Recent Posts

Hello Costakis, thanks for your input. Unfortunately, as the room is quite small there are not that many options for me to place the speakers. :-(

So I opted for trying out several more changes in placement and monitoring the effect with GLM. It seems to me that an asymmetrical placement is favorable because there are less sound cancellations. Subwoofer response is quite linear from 30 to 80 Hz now and it still integrates well with the main speakers when crossover is set to 80 Hz. The right speaker placement causes a huge cancellation below 70 Hz and both main speakers don't seem to like the range between 90 and 100 Hz. But after all now I am satisfied.